Abstract [en]

This Master Thesis describes the development of a casing for a disposable weathersonde for one-time use in the troposphere. The purpose was to examine how the casing could be designed to allow for use as both a radiosonde and a dropsonde, and how the environmental impact of the product's end-of-life phase could be reduced.

The work process was based on a product development process developed by Ulrich and Eppinger (2008). A pre-study was conducted which resulted in a requirement specification that formed the basis for concept generation. The concepts were evaluated and the most promising ones were tested using physical prototypes and virtual simulations until a final design had been established.

The work resulted in a cylindrical tube of cellulose diacetate which envelops most of the weathersonde's circuit board and leaves selected components exposed. At each end of the tube there are two semi-cylindrical corks made of natural cork that seal the openings. A thin screen of cellulose diacetate in the shape of four quarter-circles is attached to one end of the cylinder and brakes the fall to the desired speed. When used as a dropsonde the screen also ensures that the casing falls in a stable manner and in the correct orientation.

The environmental impacts in the end-of-life phase were identified mainly as plastic waste and toxic emissions from the electronic components. As there appeared to be no realistic way to permanently encapsulate the electronic components and prevent the release of toxins, it was instead decided to counteract the long-term effects of plastic waste. All parts of the casing thus consist of biodegradable materials. It was also found that in there are good prospects for the use of biodegradable casings even for weathersondes that are used at higher altitudes, and that the environmental impact can possibly be reduced further through the use of green electronics in the future.